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Abstract(s)
Atualmente, a indústria agroalimentar portuguesa já começa a prestar especial
atenção no que diz respeito ao consumo de matérias-primas e à produção de resíduos. No
entanto, a sua principal aplicação continua a ser a alimentação animal ou o uso como
fertilizantes. Recentemente, demonstrou-se que os resíduos resultantes das podas,
nomeadamente da indústria vinícola, podem ser potenciais fontes de compostos bioativos
com propriedades benéficas para a saúde. Deste modo, a recuperação destes compostos a
partir de resíduos e posterior aplicação num produto alimentar ou cosmético permitiria às
empresas reduzir os custos de tratamento e até mesmo criar lucros adicionais, o que se
refletiria na sua competitividade.
Numa primeira fase deste trabalho, pretende-se extrair diferentes compostos
bioativos a partir de resíduos de biomassa, nomeadamente das podas dos mirtilos,
aplicando a extração convencional e a extração assistida por microondas. Os extratos
obtidos foram caracterizados por diferentes métodos espectrofotométricos, tais como
TPC, TFC, DPPH, FRAP e ABTS, para avaliar as suas propriedades benéficas e os
resultados expressos em teor de peso seco de biomassa (dw). Das técnicas de extração
testadas, a extração assistida por microondas foi a que se revelou mais eficiente.
Relativamente às amostras analisadas, a variedade Duke 2019 foi a que obteve TPC mais
elevado (67,9 ± 1,7 mg GAE/g dw). No que diz respeito à atividade antioxidante,
diferentes ensaios produziram respostas diferentes, sendo que no método FRAP destacou se a variedade Bluecrop 2019 (49,3 ± 3,5 mg AAE/g dw), no método DPPH• a amostra
Duke 2020 foi a que obteve melhores resultados (92,2 ± 5,0 mg TE/g dw) e no método
ABTS•+ a amostra Duke 2019 (101 ± 6 mg AAE/g dw). Posteriormente, determinou-se
por HPLC-DAD quais os compostos individuais que estão a contribuir para as
propriedades exibidas pelos extratos obtidos. Nesta análise usou-se a variedade Duke
2019 sendo que os compostos identificados em maior concentração foram os ácidos
elágico e vanílico, e da família dos flavonoides destacou-se a catequina e a epicatequina
para ambas as técnicas de extração testadas.
Numa segunda fase foi realizada uma avaliação da presença de múltiplos
contaminantes nas amostras em estudo. Para isso, analisou-se a presença de pesticidas
(organoclorados, organofosforados e piretróides), policlorobifenilos e retardantes de
chama. Utilizou-se o método de extração QuEChERS e uma limpeza por extração em
fase sólida dispersiva (d-SPE) e de seguida foram analisados os compostos por cromatografia gasosa acoplada a dois detetores diferentes (GC-FPD e GC-ECD). Após a
análise de todas as amostras, apenas foi detetado e quantificado o cloropirifos-metilo na
amostra de podas de mirtilo (Bluecrop 2019). Apesar de não existir legislação para este
tipo de amostra, quando avaliada a concentração detetada segundo a Diretiva 2005/72/CE
da Comissão da União Europeia para mirtilos, a concentração encontrada é abaixo do
limite máximo permitido. Desta forma foi possível verificar que os extratos analisados
das podas dos mirtilos encontram-se seguros relativamente aos contaminantes avaliados
neste trabalho, para poderem ser incorporados em diversas aplicações como por exemplo
na indústria alimentar
Currently, the Portuguese agri-food industry is beginning to pay special attention to the consumption of raw materials and the production of waste. However, its main application remains in animal feed or as fertilisers. Recently, it has been shown that wastes from pruning, particularly from the wine industry, may be a potential source of bioactive compounds with health-enhancing properties. Thus, the recovery of these compounds from waste and subsequent application in food or cosmetic products would allow to the companies to reduce treatment costs and even create additional profits, which would be reflected in their competitiveness. In the first phase of this work, is intended to extract different bioactive compounds from biomass residues, namely blueberry pruning, applying conventional and microwave-assisted extractions. The obtained extracts were characterized by different spectrophotometric methods, such as total phenolic content (TPC), total flavonoid content (TFC), DPPH, FRAP, and ABTS, to evaluate their beneficial properties. From the tested extraction techniques, microwave-assisted extraction reveals to be more efficient. Concerning the analysed samples, Duke 2019 variety presented the highest TPC (67.9 ± 1.7 mg GAE/g dw). Regarding the antioxidant activity, different assays produced different results, namely in the FRAP method the Bluecrop 2019 variety was highlighted (49.3 ± 3.5 mg AAE/g dw), in the DPPH• method the Duke 2020 sample was the one who obtained the best results (92.2 ± 5.0 mg TE/g dw) and in the ABTS•+ method the Duke 2019 sample also highlighted (101 ± 6 mg AAE/g dw). Subsequently, it was determined by HPLC-DAD which individual compounds were contributing to the properties displayed by the obtained extracts. In this analysis, the Duke 2019 variety was used and the compounds identified in the highest concentration were the ellagic and vanillic acids, and from the flavonoid family it was highlighted the catechin and epicatechin for both extraction techniques tested. In the second phase of this work, a chemical hazard assessment was carried out in the samples under study. For this, all the samples were analyzed and the presence of multiple contaminants such as pesticides (organochlorine, organophosphorus and pyrethroids), PCB and Flame Retardants were evaluated. The QuEChERS extraction method and a dispersive solid phase extraction cleaning (d-SPE) were used as a extraction method and the compounds were analyzed by gas chromatography (GC-FPD and GC ECD). After the analysis of all samples, only chlorpyrifos-methyl was found a quantified in a Bluecrop 2019 sample. Although there is no legislation for this type of sample, the concentration found was in accordance (below maximum residue level) with Directive 2005/72/EC of the Commission of the European Union for blueberries. Thus, it was possible to verify that the extracts analyzed from the pruning of blueberries are safe, for the compounds under study, in order to be incorporated in several applications, namely in food
Currently, the Portuguese agri-food industry is beginning to pay special attention to the consumption of raw materials and the production of waste. However, its main application remains in animal feed or as fertilisers. Recently, it has been shown that wastes from pruning, particularly from the wine industry, may be a potential source of bioactive compounds with health-enhancing properties. Thus, the recovery of these compounds from waste and subsequent application in food or cosmetic products would allow to the companies to reduce treatment costs and even create additional profits, which would be reflected in their competitiveness. In the first phase of this work, is intended to extract different bioactive compounds from biomass residues, namely blueberry pruning, applying conventional and microwave-assisted extractions. The obtained extracts were characterized by different spectrophotometric methods, such as total phenolic content (TPC), total flavonoid content (TFC), DPPH, FRAP, and ABTS, to evaluate their beneficial properties. From the tested extraction techniques, microwave-assisted extraction reveals to be more efficient. Concerning the analysed samples, Duke 2019 variety presented the highest TPC (67.9 ± 1.7 mg GAE/g dw). Regarding the antioxidant activity, different assays produced different results, namely in the FRAP method the Bluecrop 2019 variety was highlighted (49.3 ± 3.5 mg AAE/g dw), in the DPPH• method the Duke 2020 sample was the one who obtained the best results (92.2 ± 5.0 mg TE/g dw) and in the ABTS•+ method the Duke 2019 sample also highlighted (101 ± 6 mg AAE/g dw). Subsequently, it was determined by HPLC-DAD which individual compounds were contributing to the properties displayed by the obtained extracts. In this analysis, the Duke 2019 variety was used and the compounds identified in the highest concentration were the ellagic and vanillic acids, and from the flavonoid family it was highlighted the catechin and epicatechin for both extraction techniques tested. In the second phase of this work, a chemical hazard assessment was carried out in the samples under study. For this, all the samples were analyzed and the presence of multiple contaminants such as pesticides (organochlorine, organophosphorus and pyrethroids), PCB and Flame Retardants were evaluated. The QuEChERS extraction method and a dispersive solid phase extraction cleaning (d-SPE) were used as a extraction method and the compounds were analyzed by gas chromatography (GC-FPD and GC ECD). After the analysis of all samples, only chlorpyrifos-methyl was found a quantified in a Bluecrop 2019 sample. Although there is no legislation for this type of sample, the concentration found was in accordance (below maximum residue level) with Directive 2005/72/EC of the Commission of the European Union for blueberries. Thus, it was possible to verify that the extracts analyzed from the pruning of blueberries are safe, for the compounds under study, in order to be incorporated in several applications, namely in food
Description
Keywords
Podas de mirtilos Valorização Extração convencional Extração assistida por microondas Polifenóis Atividade antioxidante Contaminantes Pesticidas Blueberry pruning Valorization Convencional extraction Microwave-assisted extraction Polyphenols Antioxidant activity Contaminants Pesticides